Backup - Unix and Macintosh File Systems

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Overview

Supported Backup Types

Unix and Macintosh File System Backup Jobs

• Back up NFS-Mounted File Systems
• Locked/Open Files
• Effect of Data Types on Backups by Macintosh/Unix File System iDataAgents
• Using Classic File Scan or Data Classification Enabler for Backups

Back up VMware Virtual Machines

Maximum Filename Length for Unix File System iDataAgent Backups

Handling Files with non-ASCII Characters

Backing up Symbolic Links

Backing up Raw Devices

QSnap Enabled Backups

Backup Considerations for This Agent

Filter File Systems for Backup

Advanced Backup Options

Overview

Plan your backup jobs for this agent by reviewing the following information:

• For an overview of backup jobs, see Backup Data.
• For a list of supported data types for this agent, see Supported Data Types.
• For information on subclients, see Subclients
  • For information on configuring subclients for this agent, see Subclients - Unix/Macintosh File Systems.
  • For information on excluding data via subclients, see Excluding Data from Data Protection Operations.

Supported Backup Types

This agent supports the following backup types:

• Full Backups
• Incremental Backups
• Differential Backups
• Synthetic Full Backups

Unix and Macintosh File System Backup Jobs

These agents have the following unique functionality.

• Back up NFS-Mounted File Systems
• Locked/Open Files
• Effect of Data Types on Backups by Unix File System iDataAgents
• Preserving the File Access Time

Back up NFS-Mounted File Systems

If you keep critical data on an NFS-mounted file system, and if the computer on which the file system resides is not itself backed up, you can secure the mounted file system data by including it in the contents of a client computer on which the file system is NFS-mounted.

You must explicitly include an NFS-mounted file system in the contents of one of the subclients on the client computer as described in the following procedure.

If the NFS-mounted file system becomes unavailable before or during a backup/restore operation, a specific condition may result based on the status of the file system.  If the file system is soft-mounted, backup operations will fail.  If the file system is auto-mounted, backup operations may fail.  If the file system is not available during a restore, data may be restored to the mount point directory.

Backups hang if a hard NFS mount becomes stale. Therefore, to allow backups to complete, you must clear any stale NFS mounts.

Locked/Open Files

There are two types of file locks used by the Unix file system: advisory locks and mandatory locks. Files with an advisory lock are available to multiple users and applications. Files with mandatory locks cannot be used by any other user or application other than the current user. Files with a mandatory lock are skipped during the backup process and their file names and paths are logged to the Backup Job History log. You can use the CommCell Console to examine this log to determine if any files were skipped. The system automatically attempts to obtain any skipped files in the next backup.

Note that this does not apply to AIX clients and that the Macintosh File System supports only advisory locks.

Effect of Data Types on Backups by Macintosh/Unix File System iDataAgents

Backup jobs may have certain restrictions related to the type of file the agent is backing up.

See Effect of Data Types on Backups by Unix File System iDataAgents and Effect of Data Types on Backups by Macintosh File System iDataAgent for more information.

Using Classic File Scan or Data Classification Enabler for Backups

When configuring Unix File System backup sets, Classic File Scan is selected as the default method for scanning files to determine which files have changed and/or have been backed up. For all Unix File System iDataAgents, you can select Use Data Classification for the same purpose if the Data Classification Enabler is installed on the client. The preferred option is the Data Classification Enabler because it is the fastest scan method.

Classic File Scan is always used when files or file level wildcards are used to define subclient content. See Subclient Content Considerations for more information.

The options you set for classic file scan will be used whenever classic file scan is called (these appear grayed out unless classic file scan is selected). For example, you can select classic file scan, pick your options, and then Data Classification. In this case the Data Classification Enabler will be used, but your selected options for classic file scan will be saved and used whenever the classic file scan is called.

See Use Classic File Scan or Data Classification Enabler for step-by-step instructions on changing your selection.

Preserving the File Access Time

This option allows you to prevent the file access time from being changed for Windows/Unix/Macintosh File System iDataAgents as a result of running data protection operations on the client. When this option is selected, the file access time will be preserved. See Preserve the File Access Time for step-by-step instructions.

Back up VMware Virtual Machines

The data that resides on the virtual machines for VMware ESX Server can be backed up using an appropriate iDataAgent, in a variety of ways. This data can be Unix data as well as data for different platforms (e.g., Windows, NetWare, etc.) Backing up VMware virtual machines requires that the appropriate iDataAgent(s) be installed and that you create and apply the Pre- and Post-Backup scripts needed to snapshot the virtual machines. Also, you can use Command Line Interface to perform backups.

For step-by-step procedures for backing up VMware ESX Server 2.5.x Virtual Machines, see Back up a VMware ESX Server 2.5.x Virtual Machine.

For more information about backing up VMware ESX Server 3.x Virtual Machines, see Back up a VMware ESX Server 3.x Virtual Machine.

Maximum Filename Length for Unix File System iDataAgent Backups

The names of files (including the path) to be backed up by any Unix File System iDataAgent except the AIX File System iDataAgent cannot contain more than 1024 characters. For the AIX File System iDataAgent, the names of such files (including the path) cannot contain more than 1023 characters.

Handling Files with non-ASCII Characters

Files containing "international" (non-ASCII) characters can be backed up and restored as long as the appropriate locale is set correctly on the Unix/Linux server. "International" characters are those characters that fall outside of the ASCII character set (i.e., the character code for each such character is higher than 127). Since most Unix systems do not set a locale by default, you should configure the locale to ensure that the affected file names will be stored properly and that backups and restores will run successfully.

The following sections describe the configuration settings required to back up and restore files with names containing characters outside of the ASCII character set .

Once configured, these settings enable you to:

• Back up files with names containing non-ASCII characters
• Restore file names containing non-ASCII characters without distortion
• Properly display files with non-ASCII characters when browsing subclient content or backup data.

Configuring the Locale

Usually, UNIX systems have several locales installed. One of them should be selected by environment variable LANG, LC_CTYPE or LC_ALL in the system profile (/etc/profile or similar). The locale defines how to encode non-ASCII file name characters.

For example, if you want to store files with Russian names encoded using the KOI-8R character encoding scheme, set the system locale to ru.koi8-r as follows:

To configure the locale:

Set the Locale

1. Stop services as described in Stop Services on Unix.
2. Run the locale -a command to check which locales are installed on the server.
3. Run the locale command (with no options) to determine which locale is currently set on the server. Output similar to the following will display:
   
   LANG=en_US.iso885915
   LC_CTYPE="en_US.iso885915"
   LC_NUMERIC="en_US.iso885915"
   LC_TIME="en_US.iso885915"
   LC_COLLATE="en_US.iso885915"
   LC_MONETARY="en_US.iso885915"
   LC_MESSAGES="en_US.iso885915"
   LC_ALL=
   
   This output shows that the en_US.iso885915 locale for the LANG environment variable is currently set.
4. To set the locale, simply set (in this case) the LC_CTYPE environment variable to the desired locale. For example:
   
   LC_CTYPE=ru.koi8-r
5. Export the locale as follows:

   # export LC_CTYPE

Now, if you run the locale command again, the following output should display:

LANG= en_US.iso885915
LC_CTYPE="ru.koi8-r"
LC_NUMERIC="ru.koi8-r"
LC_TIME="ru.koi8-r"
LC_COLLATE="ru.koi8-r"
LC_MONETARY="ru.koi8-r"
LC_MESSAGES="ru.koi8-r"
LC_ALL=

Determine if the Locale Works

6. From the same shell or login session, restart the services as described in Start Services on Unix.
7. Run a small test backup of the affected directory. If an error occurs, go back to Step 4; otherwise, go to the next step.

Include the Locale in the Startup Script

8. A properly configured system will have the correct locale set in one of the operating system startup scripts (e.g., /etc/profile). If you have reservations about changing the locale for the entire system, you may make the following changes to the Calypso startup scripts by editing the /opt/simpana/galaxy_vm file. Note that the changes will not be preserved during upgrades.
   
   LC_CTYPE=ru.koi8-r
   export LC_CTYPE

Setup Complete

9. To update the CRC consistency checking, run the following command as "root" from the Base directory:
   
   ./updatecrc32 galaxy/Base/Galaxy
10. Reboot the server to allow the iDataAgent to start with the correct locale settings.

Sample settings in TotalNET Advanced Server (TAS)

It is very important to ensure that the selected locale corresponds to the actual character encoding scheme used to encode non-ASCII file names.

For example, Solaris partitions can be exported to Macs by TotalNET Advanced Server, which could emulate AppleTalk protocol allowing Macs to connect to Solaris box and use its file system. It was important to configure TotalNET Advanced Server (TAS) so that it encoded the file names properly on the Solaris disk.

The following settings are required for computers with Solaris 8 to export their disks to Macs with Japanese software:

1. Host character set in TAS System must be set to euc-jp.

   The host character set can be accessed using the following options in the TAS system: TAS System -> TAS System Administration -> TAS System Setup

2. Solaris locale must be set to ja_JP.eucJP.
3. Client character set in the MAC computers must be set to mac-shift-jis.
4. The client character set can be accessed using the following options in the MAC computer: AppleTalk Realm -> Manage AppleTalk File Services -> Configuration

   Note that in this case the Japanese locales and conversion filters are not available on the Solaris 8 system until the following packages are installed:

   • SUNWjfpu
   • SUNWjiu8
   • SUNWjiu8x
   • SUNWjeuc.

The correct Client character set in MAC computer allows TAS to properly convert Mac file names to UNICODE. Similarly the correct Host character set in Solaris allows TAS to store these file names in a way that the rest of Solaris software (including the iDataAgent) could understand after setting the system locale to ja_JP.eucJP.

Backing up Symbolic Links

For the Unix File System iDataAgents, you can back up symbolic links that are part of the subclient content. However, when you back up the symbolic links for a directory or file, ensure that the directory or file is present in the subclient content.

Backing up Raw Devices

Selected agents can be configured to back up raw device files, including block and character, that are either explicitly identified or referenced via one or more symbolic links.  However, note the following:

• Only full backups are supported. All other backup types do not work.
• Restartability of backup jobs is not supported. Therefore, be sure to run such jobs under high priority.
• Number of bytes backed up is always displayed as '0' on the CommCell
  Console even for a successful backup.  However, the correct number of backed-up bytes is displayed in Backup Job History, Restore Job History, and clBackup.log.
• Best performance can be obtained using the character device.

See Configure the Agent to Backup Raw Devices for step-by-step instructions.

QSnap Enabled Backups

When you are using supported versions of AIX, Linux, or Solaris, you can install and enable QSnap to back up locked files. See QSnap for the Unix File System iDataAgent for more information.

Filter File Systems for Backup

Consider the following:

• For AIX and Linux File System iDataAgents that support the VERITAS Cluster File System (VxCFS), you can use the sClusteredFSFilter and the sClusteredFSTypes registry keys to filter non-clustered and clustered file systems from your backups. These registry settings can be used to prevent backing up multiple copies. Without this feature enabled in a clustered environment, if "/" is backed up, all the clustered file systems under "/" are backed up from the physical machine as well as from the virtual machine. With this feature enabled in a clustered environment, if "/" is backed up from a physical machine, only non-clustered file systems are backed up; but if "/" is backed up from a virtual machine, only clustered file systems are backed up.

• Filters can be used in conjunction with the "Items That Failed" list on the data protection Job History Report to eliminate backup or archive failures by excluding items which consistently fail that are not integral to the operation of the system or applications. Some items fail because they are locked by the operating system or application and cannot be opened at the time of the data protection operation. This often occurs with certain system-related files and database application files.

  Also, keep in mind that you will need to run a full backup after adding failed files to the filter in order to remove them.

• The tmpfs, ctfs, proc, devfs and lofs (loopback) file systems are automatically skipped during backups by the Solaris File System iDataAgent.  The filters for these file systems and others can be altered by using the ignoreFStype registry key. The addition of the lofs file system as a skipped file system has an impact on the Solaris Global Zone with regard to filesystem submount points that might previously had been expected to be backed up (e.g., if the root of a zone is an lofs file system and it has the ufs, zfs, or vxfs submount file system). These submount file systems will be skipped during backup unless they are added to the subclient content.

Backup Considerations for This Agent

Before performing any backup procedures for this agent, review the following information:

• If you are backing up hard links with registry key HLINK set to Y and the appropriate hard link updates applied, ensure that there are no directories in your subclient content that are named /_CVHardLink@-@-Files_/. Otherwise, a backup of that content will not complete successfully. See the Service Pack documentation for more information on hard link updates.
• If you are backing up hard links with registry key HLINK set to Y and the appropriate hard link updates applied, and if a head hard link is removed from the subclient content between the scan and backup phase, the backup job will go to pending. In such a case, you must kill the job and start a new backup. See the Service Pack documentation for more information on hard link updates.
• Stale NFS mounts will cause the backups to hang indefinitely; therefore, ensure that there are no stale NFS mounts before starting a backup. If there are stale NFS mounts on the server, these can be avoided by adding the directory (mount) to the exclusion filter of the subclient.
• Backup failures may occur if a remote script has one or more blank lines at the top. Therefore, be sure to delete any blank lines at the top of any remote scripts.
• Files with holes can be backed up (although for Macintosh, holed files will be backed up in the conventional way). However, this type of file may use large amounts of space on the archive media.
• For HP-UX File System, whenever you back up hole files using software compression, be aware that the compression ratio will be huge.
• For Linux File System, symbolic links appear in subclient content as the target of the link.

• If you have a File Archiver Agent on the same client as your File System iDataAgent, and you want to include DataArchiver stubs in the file system incremental backups, see Including DataArchiver Stubs in Backups for more information.

• For Solaris File System, the ufsdump process works in conjunction with the nDUMPSIZE value and the nDUMPPERCENT value:
  • The ufsdump process backs up files with the minimum nDUMPSIZE default value of 500 MB. The nDUMPSIZE x registry key allows you to modify the default file size.
  • The ufsdump process backs up files with a percentage of non-hole data greater than zero and less than or equal to the nDUMPPERCENT value. The nDUMPPERCENT x registry key allows you to modify the default percentage size.

  The software uses ufsdump to back up only those files that meet the constraint on percentage data specified by nDUMPPERCENT and the minimum size specified by nDUMPSIZE. As the default value of nDUMPPERCENT is set at zero, the software does not use ufsdump by default.

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